• We invented supercritical hydrothermal synthesis method for the synthesis of organic modified nanoparticles (NPs). Under the supercritical state, the organic molecules and metal salt aqueous solutions are miscible and water molecule works as an acid/base catalyst for the reactions. Organic-inorganic conjugate NPs can be synthesized under this condition. This hybrid NPs show high affinity with the organic solvent or the polymer matrix, which leads to fabricate the organic inorganic hybrid nanomaterials with the trade-off function (super hybird nanomaterials). These hybrid materials of polymer and ceramics fabricated with NPs achieve both high thermal conductivity and easy thin film flexible fabrication, namely trade-off function.

For example, by the surface modification of BN particles by supercritical method, affinity of BN and polymers could be improved, so that high BN content of hybrid materials, thus high thermal conductivity materials, could be synthesized. Also by dispersing high refractive index NPs like TiO2 or ZrO2 into polymers transparently, we can tune the refractive index of the polymers. CeO2 nanoparticles are expected to be used for high performance catalysts. To transfer those supercritical fluid nano technologies, a consortium was launched with more than 70 companies.

• We are developing a new continuous flow type process for supercritical reactions. Under the supercritical state, the organic molecules and metal salt aqueous solutions are miscible and water molecule works as an acid/base catalyst which leads to rapid reactions. In order to apply such new reaction fields to an industrial process, it is necessary to establish the process design basis by understanding phenomena in the reaction fields, on the basis of phase equilibrium, flux and reaction kinetics theory. So while developing a process, we are doing research for the establishment of the process design basis.

Examples are a process for the synthesis of organic modified nanoparticles (MPs), a process for the pretreatment and solubilization of biomass in the supercritical/subcritical water and a process for the refinery of heavy oil in the supercritical water.

• Hybrid materials that show multi-functions of polymer and nanoparticles are expected to be used in future industries, and thus many research and development have been actively conducted. However, since the affinity of polymer and inorganic nanoparticles is very low, in most of the cases, properties of different materials are incompatible in the hybrid materials. To create the hybrid materials with incompatible multi-functions has been considered a difficult task.
• However, by using supercritical fluid technology, we have succeeded in making hybrid materials with incompatible multi-functions.

Now, variety of hybrid materials are being developed, including
・Transparent, flexible, high reflective index, and high fabricability,
・Flexible, high heat conductivity, low electric resistivity, and high fabricability.

• Our research group has succeeded in synthesizing various metal oxide nanoparticles with controlled size and exposure crystal planes by using organic modifiers under supercritical water conditions. The oxygen storage/release capacity of those materials in the low-temperature region is very high, and the reforming reaction of oxidative hydrocarbon proceeds at a significant rate. Besides, by combining the supercritical CO2 drying method, we have succeeded in forming a complex in which oxide nanoparticles are dispersed at a high concentration on the surface of the porous material, realizing both high oxygen storage/release capability and stability.

Low-temperature reforming reaction of biomass wastes, heavy oils, and methane. In the future, it is expected to be a technology that will lead to the construction of a low-carbon society, including CO2-free complete recycling of waste plastics.

• Scanning tunneling microscope (STM) and atomic force microscope (AFM) are among a few microscopes which enable a direct observation of atomic scale structures of materials. If compared with other electron microscope like transmission electron microscope (TEM), the energy of the electron used for STM is very low that has a big advantage of low damage for sample. Thus STM and AFM are regarded as the most important tools to characterize materials in nanotechnology. The research is now developing from a mere observation of the shape of material to the characterization specific properties of materials with an atomic scale resolution. These properties include spin and molecule vibration; well established techniques like ESR/NMR and infrared-spectroscopy requires more than billions of molecules to obtain data, while STM can obtain these data for a single molecule.
• We are interested following issues and like to have a collaboration with industrial companies.
• 1. Molecule-scale morphological characterization of soft-material, polymers and bio material.
• 2. Site specific vibration spectroscopy of molecules with an atomic resolution.
• 3. Single spin detection with ESR-STM method
• 4. Developing atom-scale characterization tool

• Microstructure represents various kinds of heterogeneities in the metallic materials, i.e., grains, component phase, lattice defects and chemical inhomogeneity such as impurity/alloying elements. It can be modified through control of phase transformation/precipitation and deformation/recrystallization by adjusting compositions of materials and/or through processing routes (heat treatment, deformation). Such expertise in micro/nanostructure control is very important in production of current materials from viewpoints of energy saving and recycling in structural materials such as steels and titanium alloys.
• We attempt to apply more advanced control of micro/nanostructures, such as atomic structures of crystalline interfaces, chemistory in an atomic scale (e.g., segregation) and so on. Fundamentals of microstructure formation (thermodynamics, kinetics, crystallography) are examined both theoretically and experimentally to clarify key factors for microstructure control. Another important aspect in our research is the improvement of mechanical property by microstructure manipulation.

Possibilities to establish new functions (e.g., superplasticity, shape memory/superelasticity) as well as superior mechanical properties (e.g., ultrahigh strength with high toughness/ductility) is also explored.

• The main research subjects in this group are the experimental investigations of the organic molecular conductors. The characteristic properties of the organic materials are multiple flexibilities owing to the assemble structure of nanometer-size molecules. This flexbility comes up recently for developing the organic electronic devices. We explore the fundamental electronic properties of the organic molecular materials which have wide range of the ground states from superconductivity to insulating states resulting from the strongly correlated electrons in the molecular pi-orbital. Such features are closely connected to flexible and multiple degrees of freedom in charge, spin, molecular latticeand molecules themselves. We are actively studying on the interesting and important issues in the condensed matter physics from the viewpoints of the characteristic flexbility of the organic molecular materials. We are prepared to provide academic consultations to companies interested in our research.

• Recently, with a spread of high definition video streaming services and ubiquitous network, development of high-quality, ultra-realistic and low-power display systems has been demanded. We have been studying physical properties of liquid crystal materials, precise control technique of polarization, high performance liquid crystal display (LCD) devices and its application to the advanced display systems for the realization of new media such as electric paper display and digital signage display, and low-energy society. We established a polarization control technology which realizes a precise control of polarization with liquid crystal materials. By using this world-leading technology, we have been studying the control of the surface alignment of liquid crystal molecules and developed a wide-viewing angle and fast switching liquid crystal display, ultra-high definition field-sequential-color display (Fig. 1), ultra-low power reflective full-color display (Fig. 2) and large-size high-quality display system.
• We are also studying the ultra-realistic display systems such as a spatial 3D display and a multiple directional viewing display based on the precise light control technique as a next generation interactive communication technologies (Fig.3). We hope to conduct collaborative research with a willing company for a practical application of this technology in industry.

• Most innovations have been triggered by advent of new materials. We focus on to explore new inorganic materials and their synthesis routes on the basis of our knowledge about the material design and various materials processing technologies. We develop proton conducting phosphate glasses working at intermediate temperatures and narrow gap oxide semiconductors applicable in visible and NIR regions. Thin-film solar cells, fuel cells using those materials are also developing.

We focus on oxide semiconductors and proton conducting electrolytes and electrodes in order to apply them in solar cells, fuel cells, light-emitting devices. But, applicable area of our technologies is not limited in those applications.